A great variety of probes are used in today's type of vehicle construction. First of all, there are probes which have two pump electrodes disposed on a solid electrolyte, as described, for example, in German Patent Application No. DE 10 2007 009 157 A1 or in German Patent Application No. DE 10 2007 020 970 A1. Moreover, there are also what are termed broadband lambda probes having two cells, as described, for example, in German Patent Application No. DE 10 2007 057 707 A1. These probes are used to measure the concentration of a gas component in the exhaust gas of the internal combustion engine. Broadband lambda probes are made generally of a combination of a conventional concentration probe (Nernst probe) acting as a galvanic cell, as well as a limit-current cell or pump cell. A voltage is applied from outside to the pump cell, which is of the same kind as a customary concentration cell. If the voltage is great enough, what is termed a limiting current ensues, which is proportional to the difference in the oxygen concentration on both sides of the probe. Oxygen atoms are transported—as a function of polarity—with the current values. Owing to an electronic regulating circuit, the pump cell always supplies exactly enough oxygen from the exhaust gas via a very narrow diffusion gap to the concentration probe, so that the condition λ=1 prevails at it. In response to excess air in the exhaust gas (lean-combustion range), oxygen is pumped away. In the case of low residual oxygen content in the exhaust gas (rich-mixture range), oxygen is supplied by reversing the pump voltage. The specific pump current forms the output signal. The output-signal line of such broadband lambda probes is connected to the engine control unit.
If, for example, a lambda probe is now replaced, then purely as a matter of principle, a probe of the same type must always be used. An exchange of lambda probes is not readily possible, since their output signals cannot be processed properly in the control unit.